Which Vitamin Deficiency Causes Hair Loss

Hair loss in women and men is a common concern, and while it is often linked to hormones, genetics, or ageing, vitamin deficiencies can also play a major role. Hair relies on a steady supply of nutrients to grow strong and healthy, and when the body is lacking in certain vitamins, the hair follicles may weaken or shift into a shedding phase. Understanding which vitamin deficiency causes hair loss can help identify whether a nutritional gap is contributing to thinning hair and what steps can be taken to improve overall hair health.

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The Importance of Vitamins for Hair Health

Vitamins are essential for maintaining the hair growth cycle, which involves phases of active growth, resting, and natural shedding. When the body has enough of the right nutrients, hair grows thick, shiny, and resilient. However, when deficiencies occur, hair growth may slow, follicles may weaken, and shedding can become more noticeable. This type of hair loss is usually diffuse thinning across the scalp rather than patchy bald spots, and the good news is that once the deficiency is corrected, hair often improves.

Vitamin D Deficiency and Hair Loss

One of the most researched vitamins linked to hair loss is vitamin D. This vitamin helps with the creation of new hair follicles and supports overall follicle health. Low vitamin D levels are often associated with conditions such as alopecia areata and general hair thinning. Because vitamin D also plays a key role in bone and immune health, a deficiency may affect the body in several ways beyond just hair. In the UK, low vitamin D levels are common during the winter months when sunlight is limited, making supplementation an important consideration.

The Role of Vitamin B12

Vitamin B12 is another vital nutrient for healthy hair growth. It supports the production of red blood cells, which carry oxygen to the scalp and hair follicles. Without enough oxygen and nutrients being delivered to the follicles, hair may become brittle, weak, and prone to shedding. A deficiency in vitamin B12 is particularly common among those who follow a strict vegan or vegetarian diet, as it is primarily found in animal products. Addressing a deficiency through diet or supplements can often improve hair health over time.

Iron and Its Connection to Hair Shedding

Although technically a mineral rather than a vitamin, iron is closely tied to hair loss and is worth mentioning here. Iron deficiency is one of the most common nutritional causes of hair shedding, especially in women. Low iron reduces the amount of oxygen available to the follicles, leading to increased hair fall. This type of loss is often gradual and widespread, but once iron levels are restored, many people notice improvement in both hair growth and texture.

Other Vitamins That Influence Hair Growth

Several other vitamins play supportive roles in maintaining strong, healthy hair. Vitamin C helps with collagen production and improves the absorption of iron, making it particularly important for those prone to low iron levels. Vitamin A supports cell growth, including that of the hair follicle, although too much vitamin A can actually contribute to hair loss, highlighting the importance of balance. Vitamin E works as an antioxidant that supports scalp circulation, which in turn promotes a healthy environment for hair growth.

Collagen and Nutritional Support

Collagen is another key player in hair health, working alongside vitamins to provide structure and strength to both the hair shaft and the scalp. It contains amino acids that are the building blocks of keratin, the main protein in hair. While collagen itself is not a vitamin, it complements the role of nutrients by helping hair stay strong, shiny, and resilient. Combined with a balanced intake of vitamins, collagen can support a healthier hair growth cycle, particularly during times of stress, illness, or hormonal change.

Recognising Signs of Deficiency

Identifying whether hair loss is caused by vitamin deficiency can be difficult, as shedding is often influenced by many factors. However, if hair loss is accompanied by other symptoms such as fatigue, brittle nails, dry skin, or a pale complexion, nutritional deficiencies may be playing a role. Blood tests arranged by a GP can confirm whether low vitamin levels are contributing and whether supplements may help restore balance.

Final Thoughts

The most common vitamin deficiencies linked to hair loss include vitamin D and vitamin B12, with iron also being a major factor. Other vitamins like A, C, and E contribute to overall hair strength and growth. Maintaining a healthy, balanced diet and considering supplements when necessary can help keep hair in its best condition. Since hair takes time to respond to improvements in nutrition, patience is key, but most people find that restoring vitamin levels brings noticeable results.